Learn to implement a fundamental HTML file add type utilizing the Leaf template engine and Vapor, all written in Swift in fact.
Constructing a file add type
Let’s begin with a fundamental Vapor challenge, we’re going to make use of Leaf (the Tau launch) for rendering our HTML information. You must observe that Tau was an experimental launch, the modifications have been reverted from the ultimate 4.0.0 Leaf launch, however you’ll be able to nonetheless use Tau in the event you pin the precise model in your manifest file. Tau might be printed afterward in a standalone repository… 🤫
// swift-tools-version:5.3
import PackageDescription
let package deal = Package deal(
title: "myProject",
platforms: [
.macOS(.v10_15)
],
dependencies: [
.package(url: " from: "4.35.0"),
.package(url: " .exact("4.0.0-tau.1")),
.package(url: " .exact("1.0.0-tau.1.1")),
],
targets: [
.target(
name: "App",
dependencies: [
.product(name: "Leaf", package: "leaf"),
.product(name: "LeafKit", package: "leaf-kit"),
.product(name: "Vapor", package: "vapor"),
],
swiftSettings: [
.unsafeFlags(["-cross-module-optimization"], .when(configuration: .launch))
]
),
.goal(title: "Run", dependencies: [.target(name: "App")]),
.testTarget(title: "AppTests", dependencies: [
.target(name: "App"),
.product(name: "XCTVapor", package: "vapor"),
])
]
)
Now in the event you open the challenge with Xcode, don’t overlook to setup a customized working listing first, as a result of we’re going to create templates and Leaf will search for these view information beneath the present working listing by default. We’re going to construct a quite simple index.leaf file, you’ll be able to place it into the Assets/Views listing.
File add instance
As you’ll be able to see, it’s a regular file add type, whenever you need to add information utilizing the browser you all the time have to make use of the multipart/form-data encryption kind. The browser will pack each area within the type (together with the file information with the unique file title and a few meta data) utilizing a particular format and the server utility can parse the contents of this. Luckily Vapor has built-in help for straightforward decoding multipart type information values. We’re going to use the POST /add route to avoid wasting the file, let’s setup the router first so we will render our major web page and we’re going to put together our add path as nicely, however we are going to reply with a dummy message for now.
import Vapor
import Leaf
public func configure(_ app: Utility) throws {
/// config max add file measurement
app.routes.defaultMaxBodySize = "10mb"
/// setup public file middleware (for internet hosting our uploaded information)
app.middleware.use(FileMiddleware(publicDirectory: app.listing.publicDirectory))
/// setup Leaf template engine
LeafRenderer.Possibility.caching = .bypass
app.views.use(.leaf)
/// index route
app.get { req in
req.leaf.render(template: "index")
}
/// add handler
app.submit("add") { req in
"Add file..."
}
}
You possibly can put the snippet above into your configure.swift file then you’ll be able to attempt to construct and run your server and go to http://localhost:8080, then attempt to add any file. It gained’t really add the file, however a minimum of we’re ready to jot down our server facet Swift code to course of the incoming type information. ⬆️
File add handler in Vapor
Now that we now have a working uploader type we should always parse the incoming information, get the contents of the file and place it beneath our Public listing. You possibly can really transfer the file anyplace in your server, however for this instance we’re going to use the Public listing so we will merely check if everthing works through the use of the FileMiddleware. In the event you don’t know, the file middleware serves all the pieces (publicly out there) that’s positioned inside your Public folder. Let’s code.
app.submit("add") { req -> EventLoopFuture in
struct Enter: Content material {
var file: File
}
let enter = attempt req.content material.decode(Enter.self)
let path = app.listing.publicDirectory + enter.file.filename
return req.utility.fileio.openFile(path: path,
mode: .write,
flags: .allowFileCreation(posixMode: 0x744),
eventLoop: req.eventLoop)
.flatMap { deal with in
req.utility.fileio.write(fileHandle: deal with,
buffer: enter.file.information,
eventLoop: req.eventLoop)
.flatMapThrowing { _ in
attempt deal with.shut()
return enter.file.filename
}
}
}
So, let me clarify what simply occurred right here. First we outline a brand new Enter kind that can comprise our file information. There’s a File kind in Vapor that helps us decoding multipart file add types. We are able to use the content material of the request and decode this sort. We gave the file title to the file enter type beforehand in our leaf template, however in fact you’ll be able to change it, however in the event you achieve this you additionally should align the property title contained in the Enter struct.
After we now have an enter (please observe that we don’t validate the submitted request but) we will begin importing our file. We ask for the situation of the general public listing, we append the incoming file title (to maintain the unique title, however you’ll be able to generate a brand new title for the uploaded file as nicely) and we use the non-blocking file I/O API to create a file handler and write the contents of the file into the disk. The fileio API is a part of SwiftNIO, which is nice as a result of it’s a non-blocking API, so our server might be extra performant if we use this as an alternative of the common FileManager from the Basis framework. After we opened the file, we write the file information (which is a ByteBuffer object, dangerous naming…) and at last we shut the opened file handler and return the uploaded file title as a future string. In the event you haven’t heard about futures and guarantees you need to examine them, as a result of they’re in all places on the server facet Swift world. Can’t look forward to async / awake help, proper? 😅
We are going to improve the add consequence web page just a bit bit. Create a brand new consequence.leaf file contained in the views listing.
File uploaded
#if(isImage):
#else:
Present me!
#endif
Add new one
So we’re going to verify if the uploaded file has a picture extension and go an isImage parameter to the template engine, so we will show it if we will assume that the file is a picture, in any other case we’re going to render a easy hyperlink to view the file. Contained in the submit add handler technique we’re going to add a date prefix to the uploaded file so we will add a number of information even with the identical title.
app.submit("add") { req -> EventLoopFuture in
struct Enter: Content material {
var file: File
}
let enter = attempt req.content material.decode(Enter.self)
guard enter.file.information.readableBytes > 0 else {
throw Abort(.badRequest)
}
let formatter = DateFormatter()
formatter.dateFormat = "y-m-d-HH-MM-SS-"
let prefix = formatter.string(from: .init())
let fileName = prefix + enter.file.filename
let path = app.listing.publicDirectory + fileName
let isImage = ["png", "jpeg", "jpg", "gif"].accommodates(enter.file.extension?.lowercased())
return req.utility.fileio.openFile(path: path,
mode: .write,
flags: .allowFileCreation(posixMode: 0x744),
eventLoop: req.eventLoop)
.flatMap { deal with in
req.utility.fileio.write(fileHandle: deal with,
buffer: enter.file.information,
eventLoop: req.eventLoop)
.flatMapThrowing { _ in
attempt deal with.shut()
}
.flatMap {
req.leaf.render(template: "consequence", context: [
"fileUrl": .string(fileName),
"isImage": .bool(isImage),
])
}
}
}
In the event you run this instance you need to be capable to view the picture or the file straight from the consequence web page.
A number of file add utilizing Vapor
By the best way, you may as well add a number of information directly in the event you add the a number of attribute to the HTML file enter area and use the information[] worth as title.
To help this we now have to change our add technique, don’t fear it’s not that sophisticated because it appears at first sight. 😜
app.submit("add") { req -> EventLoopFuture in
struct Enter: Content material {
var information: [File]
}
let enter = attempt req.content material.decode(Enter.self)
let formatter = DateFormatter()
formatter.dateFormat = "y-m-d-HH-MM-SS-"
let prefix = formatter.string(from: .init())
struct UploadedFile: LeafDataRepresentable {
let url: String
let isImage: Bool
var leafData: LeafData {
.dictionary([
"url": url,
"isImage": isImage,
])
}
}
let uploadFutures = enter.information
.filter { $0.information.readableBytes > 0 }
.map { file -> EventLoopFuture in
let fileName = prefix + file.filename
let path = app.listing.publicDirectory + fileName
let isImage = ["png", "jpeg", "jpg", "gif"].accommodates(file.extension?.lowercased())
return req.utility.fileio.openFile(path: path,
mode: .write,
flags: .allowFileCreation(posixMode: 0x744),
eventLoop: req.eventLoop)
.flatMap { deal with in
req.utility.fileio.write(fileHandle: deal with,
buffer: file.information,
eventLoop: req.eventLoop)
.flatMapThrowing { _ in
attempt deal with.shut()
return UploadedFile(url: fileName, isImage: isImage)
}
}
}
return req.eventLoop.flatten(uploadFutures).flatMap { information in
req.leaf.render(template: "consequence", context: [
"files": .array(files.map(.leafData))
])
}
}
The trick is that we now have to parse the enter as an array of information and switch each doable add right into a future add operation. We are able to filter the add candidates by readable byte measurement, then we map the information into futures and return an UploadedFile consequence with the correct file URL and is picture flag. This construction is a LeafDataRepresentable object, as a result of we need to go it as a context variable to our consequence template. We even have to vary that view as soon as once more.
Information uploaded
#for(file in information):
#if(file.isImage):
#else:
#(file.url)
#endif
#endfor
Add new information
Properly, I do know this can be a useless easy implementation, but it surely’s nice if you wish to apply or discover ways to implement file uploads utilizing server facet Swift and the Vapor framework. It’s also possible to add information on to a cloud service utilizing this method, there’s a library known as Liquid, which is analogous to Fluent, however for file storages. Presently you should use Liquid to add information to the native storage or you should use an AWS S3 bucket or you’ll be able to write your individual driver utilizing LiquidKit. The API is fairly easy to make use of, after you configure the motive force you’ll be able to add information with only a few strains of code.
